DOCSLIB.ORG

Impact of Stellar Companions on Precise Radial Velocities⋆

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Impact of Stellar Companions on Precise Radial Velocities⋆ A&A 550, A75 (2013) Astronomy DOI: 10.1051/0004-6361/201220083 & c ESO 2013 Astrophysics Impact of stellar companions on precise radial velocities D. Cunha1,2,P.Figueira1,N.C.Santos1,2,C.Lovis3, and G. Boué1,4 1 Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal e-mail: [email protected] 2 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal 3 Observatoire Astronomique de l’Université de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Versoix, Suisse 4 ASD, IMCCE-CNRS UMR 8028, Observatoire de Paris, UPMC, 77 avenue Denfert-Rochereau, 75014 Paris, France Received 23 July 2012 / Accepted 29 November 2012 ABSTRACT Context. With the announced arrival of instruments such as ESPRESSO one can expect that several systematic noise sources on the measurement of precise radial velocity will become the limiting factor instead of photon noise. A stellar companion within the fiber is such a possible noise source. Aims. With this work we aim at characterizing the impact of a stellar companion within the fiber to radial velocity measurements made by fiber-fed spectrographs. We consider the contaminant star either to be part of a binary system whose primary star is the target star, or as a background/foreground star. Methods. To carry out our study, we used HARPS spectra, co-added the target with contaminant spectra, and then compared the resulting radial velocity with that obtained from the original target spectrum. We repeated this procedure and used different tunable knobs to reproduce the previously mentioned scenarios. Results. We find that the impact on the radial velocity calculation is a function of the difference between individual radial velocities, of the difference between target and contaminant magnitude, and also of their spectral types. For the worst-case scenario in which both target and contaminant star are well-centered on the fiber, the maximum contamination for a G or K star may be higher than 10 cm s−1, on average, if the difference between target and contaminant magnitude is Δm < 10, and higher than 1 m/sifΔm < 8. If the target star is of spectral type M, Δm < 8 produces the same contamination of 10 cm s−1, and a contamination may be higher than 1m/sifΔm < 6. Key words. techniques: radial velocities – planets and satellites: detection 1. Introduction Here we address a so far unexplored mechanism that is capa- ble of distorting RV signals and creating false ones: the contam- The search for extrasolar planets is currently a very active field ination of the main spectrum by that of a (usually unresolved or of research in astronomy. Since the first discovery of Mayor otherwise undetectable) companion. We consider two different &Queloz(1995), more than 800 planets were discovered1,of cases: which 80% were detected with the radial velocity method (RV). Because it is the workhorse for planetary detections, this method 1. that of a faint gravitationally bounded companion; and received much attention from the community, which constantly 2. that of an unbound star that is aligned with the target at the increased its precision (for some of the latest results check moment of observation. Mayor et al. 2011) and tried to characterize its limitations. One of the fundamental drawbacks is that it is an indirect We assumed the target stars to be placed at the Galaxy disk edge method, and therefore one should be extremely careful with false to consider a representative case that encompasses several sce- narios of contaminant stars. We used real high signal to noise ra- positives, i.e., signals created by other planetary RV signals. The / literature provides many examples and techniques used to pin- tio (S N) observations obtained with HARPS to create the com- point these signals (e.g. Queloz et al. 2001; Santos et al. 2002; posite spectra and process these with the RV calculation pipeline Melo et al. 2007; Huélamo et al. 2008; Figueira et al. 2010)or to evaluate the impact of the contamination in the most realistic way possible. While we aim at characterizing this effect down to to average them out (Dumusque et al. 2011b,a). With the ad- −1 vent of very high precision spectrographs, such as ESPRESSO the precision level of ESPRESSO, 10 cm s , it can be assessed or CODEX (Pepe et al. 2010), the RV precision enters a new at an even lower precision level. domain, that of cm s−1, which in turn will increase the quality Although this study is performed to characterize the impact on the RV when using the cross-correlation function (CCF), of our characterization of these unwanted yet ubiquitous signals ff (e.g. Cegla et al. 2012). point spread function (PSF) modeling will also be a ected by stellar companions, if in a different way. The results of this study are particularly interesting for deep surveys in crowded fields Appendices are available in electronic form at (Kepler). http://www.aanda.org If the contaminant RV remains constant, stellar blends will 1 http://exoplanet.eu/,asof27/09/2012 only cause a undetectable contamination in the RV calculation. Article published by EDP Sciences A75, page 1 of 14 A&A 550, A75 (2013) However, if the contaminant RV is changing, if the seeing varies, Table 1. Probability of observing a binary with a mass ratio q = M2/M1 or if there are guiding problems during observations, the effect of among G-dwarf binaries for periods P < 104 days and P < 104. the contamination will no longer be constant and it might mimic the presence of a planet. As an example of a false positive caused qmax 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 by blended stars we refer to the work of Santos et al. (2002), in P < 104 days which RV measurements derived from CORALIE blended spec- P(q) [%] 12.0 16.3 13.1 12.7 12.3 12.9 6.5 1.9 2.6 3.4 6.2 tra of HD 41004 AB have unveiled a radial-velocity variation > 4 with a period of 1.3 days and a small amplitude of 50 m/s, com- P 10 days P(q) [%] 11.1 11.9 18.4 15.8 10.5 11.2 6.6 6.6 4.0 4.0 0 patible with the signal expected to be caused by a planetary com- panion to HD 41004 A. Another example is WASP-9b, which Total was discarded as a planet after it was discovered that the signal P(q) [%] 11.4 13.6 16.4 14.6 11.2 11.8 6.5 4.8 3.4 3.8 2.4 was due to a fortuitous alignment (Triaud, priv. comm.). Notes. From Duquennoy & Mayor (1991). In Sect. 2 we explain which stars we consider most likely to contribute to a shift in the RV calculation, if the star is ei- ther in a G-, K- or M-dwarf binary system, or is affected by a Table 2. Probability of observing a binary with an eccentricity e among G-dwarfs binaries for periods P < 103 days and P < 103. fortuitous alignment. Then, in Sect. 3 we describe the properties of the spectra used in our simulations. In Sect. 4 we describe the method used to scramble spectra from target star and stel- emax 0.15 0.3 0.45 0.6 0.75 0.9 1 lar companion. Results from our work, assuming the worst-case P < 103 days scenario in which both target and contaminant are well centered P(e) [%] 12.50 43.75 31.25 6.25 6.25 0.0 0.0 on the fiber, are shown in Sect. 5. The results are followed by a P > 103 days statistical analysis in Sect. 5.4, which is based on these results, P(e) [%] 5.88 11.76 23.53 14.71 20.59 23.53 0.0 but assumes a more realistic situation, in which the contaminant star may not be fiber centered. In Sect. 6 we discuss our work, Notes. From Duquennoy & Mayor (1991). and we present our conclusions in Sect. 7. Table 3. Probability of observing an M-dwarf binary with a mass ratio q = M2/M1. 2. Contaminant cases qmax 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 When one observes a target star, a secondary star may be present, P(q) [%] 0.0 1.61 5.95 10.45 12.93 13.84 14.48 13.03 14.58 13.13 even without one’s knowledge. This secondary star may be a source of contamination for the calculation of the target star’s Notes. From Janson et al. (2012). RV. Secondary/contaminants stars may appear as two different types: real binaries or fortuitous alignments. Table 4. Probability of observing an M-dwarf binary with a certain log a. 2.1. Real binaries log amax 0.25 0.5 0.75 1. 1.25 1.5 1.75 2. 2.25 2.5 In the case of a real binary system, the contaminant star will be P(log a) [%] 0.51 2.60 9.02 15.39 17.13 17.65 14.73 11.74 7.85 3.37 gravitationally bound. In this section we present the probability distributions of real binary properties that we used in our work. Notes. From Janson et al. (2012). Here, for G- and K primaries we based our study on the results of Duquennoy & Mayor (1991), who studied the For M-dwarfs we used the distributions of mass ratio, q, multiplicity among solar-type stars in the solar neighborhood.
Load more

Recommended publications
  • Li Abundances in F Stars: Planets, Rotation, and Galactic Evolution,
    A&A 576, A69 (2015) Astronomy DOI: 10.1051/0004-6361/201425433 & c ESO 2015 Astrophysics Li abundances in F stars: planets, rotation, and Galactic evolution, E. Delgado Mena1,2, S. Bertrán de Lis3,4, V. Zh. Adibekyan1,2,S.G.Sousa1,2,P.Figueira1,2, A. Mortier6, J. I. González Hernández3,4,M.Tsantaki1,2,3, G. Israelian3,4, and N. C. Santos1,2,5 1 Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal e-mail: [email protected] 2 Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal 3 Instituto de Astrofísica de Canarias, C/via Lactea, s/n, 38200 La Laguna, Tenerife, Spain 4 Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain 5 Departamento de Física e Astronomía, Faculdade de Ciências, Universidade do Porto, Portugal 6 SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, UK Received 28 November 2014 / Accepted 14 December 2014 ABSTRACT Aims. We aim, on the one hand, to study the possible differences of Li abundances between planet hosts and stars without detected planets at effective temperatures hotter than the Sun, and on the other hand, to explore the Li dip and the evolution of Li at high metallicities. Methods. We present lithium abundances for 353 main sequence stars with and without planets in the Teff range 5900–7200 K. We observed 265 stars of our sample with HARPS spectrograph during different planets search programs. We observed the remaining targets with a variety of high-resolution spectrographs.
    [Show full text]
  • Journal Pre-Proof
    Journal Pre-proof Primordial backgrounds of relic gravitons Massimo Giovannini PII: S0146-6410(20)30021-1 DOI: https://doi.org/10.1016/j.ppnp.2020.103774 Reference: JPPNP 103774 To appear in: Progress in Particle and Nuclear Physics Please cite this article as: M. Giovannini, Primordial backgrounds of relic gravitons, Progress in Particle and Nuclear Physics (2020), doi: https://doi.org/10.1016/j.ppnp.2020.103774. This is a PDF file of an article that has undergone enhancements after acceptance, such asthe addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of thearticle. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ' 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Journal Pre-proof Primordial backgrounds of relic gravitons Massimo Giovannini∗ Department of Physics, CERN, 1211 Geneva 23, Switzerland INFN, Section of Milan-Bicocca, 20126 Milan, Italy Abstract The diffuse backgrounds of relic gravitons with frequencies ranging between the aHz band and the GHz region encode the ultimate information on the primeval evolution of the plasma and on the underlying theory of gravity well before the electroweak epoch. While the temperature and polarization anisotropies of the microwave background radiation probe the low-frequency tail of the graviton spectra, during the next score year the pulsar timing arrays and the wide-band interferometers (both terrestrial and hopefully space-borne) will explore a much larger frequency window encompassing the nHz domain and the audio band.
    [Show full text]
  • Article (Published Version)
    Article The HARPS search for southern extra-solar planets. XXXII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone LO CURTO, G., et al. Reference LO CURTO, G., et al. The HARPS search for southern extra-solar planets. XXXII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone. Astronomy and Astrophysics, 2013, vol. 551, p. A59 DOI : 10.1051/0004-6361/201220415 Available at: http://archive-ouverte.unige.ch/unige:33878 Disclaimer: layout of this document may differ from the published version. 1 / 1 A&A 551, A59 (2013) Astronomy DOI: 10.1051/0004-6361/201220415 & c ESO 2013 Astrophysics The HARPS search for southern extra-solar planets XXXII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone?;?? G. Lo Curto1, M. Mayor2, W. Benz3, F. Bouchy2;5, G. Hébrard5;6, C. Lovis2, C. Moutou4, D. Naef2, F. Pepe2, D. Queloz2, N. C. Santos7;8, D. Segransan2, and S. Udry2 1 ESO – European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany e-mail: [email protected] 2 Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland 3 Physikalisches Institut Universität Bern, Sidlerstrasse 5, 3012 Bern, Switzerland 4 Laboratoire d’Astrophysique de Marseille, Traverse du Siphon, 13376 Marseille 12, France 5 Institut d’Astrophysique de Paris, UMR 7095 CNRS, Université Pierre & Marie Curie, 98bis boulevard Arago, 75014 Paris, France 6 Observatoire de Haute-Provence, CNRS/OAMP, 04870 Saint-Michel-l’Observatoire, France 7 Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal 8 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Portugal Received 20 September 2012 / Accepted 2 January 2013 ABSTRACT The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution.
    [Show full text]
  • Exploration of Phase Modulations of Non-Transiting Exoplanets with TESS Data
    Exploration of phase modulations of non-transiting exoplanets with TESS data Neil McCulloch Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom March 1, 2021 This report aims to explore the possibility of observing phase modulations from a non transiting exoplanets using photometry from the transiting exoplanet survey satellite. By calculating or constraining parameters of orbital systems, namely: inclination, planet radius, planet equilibrium temperature and albedo, the expected amplitude of phase modulations can be estimated and fit to the observed photometric data. Planet radius was estimated as (Rp = 1.3 ± 0.2) RJ , inclination was estimated as (i = 77.5 ± 0.2) ° and geometric albedo was constrained to (Ag = 0.37 ± 0.07). By constraining albedo and calculating planet equilibrium temperature, a basic insight into non-transiting exoplanet atmospheres was gained. 1 Introduction Data from from RV surveys implies 5- 10% of solar systems with sun-like host As of 06/01/20, there are 4104 confirmed stars contain massive planets and up to detection's [1] of planets external to our so- 30% contain rocky planets [3]. Extrapolat- lar system discovered by various methods, ing these numbers to incorporate all stars notably: transit photometry, radial veloc- in the Milky Way implies our galaxy could ity (RV) and microlensing. The majority of contain billions of planets, many of which exoplanets (¡ 75%) are discovered by ob- could orbit in the habitable zone (HZ) [3]. serving a planetary transit across its host Currently „ 15 confirmed exoplanets fit star. The resulting dip in the light curve of this criteria. the star provides information about orbital period (P ) and planet radius (Rp) [2].
    [Show full text]
  • June 2017 BRAS Newsletter
    June 2017 Issue Next Meeting: Monday, June 12th at 7PM at HRPO nd (2 Mondays, Highland Road Park Observatory) Presenter: Dr. Gabriela Gonzalez, spokesperson for the LIGO Scientific Collaboration, on “Einstein, Gravitational Waves and Black Holes”. What's In This Issue? President’s Message Secretary's Summary Outreach Report - FAE Event Photos Light Pollution Committee Report Recent Forum Entries 20/20 Vision Campaign Messages from the HRPO American Radio Relay League Field Day Observing Notes – Corvus –The Crow & Mythology Like this newsletter? See past issues back to 2009 at http://brastro.org/newsletters.html Newsletter of the Baton Rouge Astronomical Society June 2017 President’s Message Summer is upon us. On June 21st, at 11:24 AM CDT, summer officially begins for the Northern Hemisphere. We have a lot of outreach requests for June; the July BRAS meeting will be our annual picnic at LIGO; and one week after the August BRAS meeting is the total eclipse of the Sun. What are your plans for the summer? Will you go somewhere to see the eclipse? The band of totality runs from Georgia across the continental US to Oregon. Last month we did outreach at the Bluebonnet Swamp’s FAE Fest/20th Anniversary event. Due to a cloud cover most of the day, there was little solar viewing, but we did interact with close to 300 people, including a former member of BRAS (about 20 years ago) who expressed interest in re-joining us. The Astronomical League has awarded Comet Observing (#91) to Coy Wagoner. Congratulations Coy! In step with the April BRAS meeting’s speaker, Dr.
    [Show full text]
  • Precise Spectroscopic Analysis of Solar- Type Stars With
    P P h D 3.º CICLO FCUP ANO h Precise spectroscopic D w P r i e t h c analysis of solar- i m s e o d s p e r e a c type stars with t t e r o a s n c d o f p a moderate and fast i s c t a r n o a t a l y t i s rotation o i s n o f s Maria Tsantaki o l a Tese de Doutoramento apresentada à r - t Faculdade de Ciências da Universidade do Porto, y p e Departamento de Física e Astronomia s t a 2015 r s D D M a r i a T s a n t a k i h P Precise spectroscopic analysis of solar-type stars with moderate and fast rotation Maria Tsantaki Centro de Astrof´ısicada Universidade do Porto Departamento de F´ısicae Astronomia, Faculdade de Ci^encias,Universidade do Porto Tese de Doutouramento Orientadores: S. G. Sousa, N. C. Santos October, 2014 To Astrophysics \May it help free minds in destroying ignorance, superstitions, and beliefs in god-like entities." Abstract In this thesis, I describe the processes of deriving the fundamental stellar parameters for solar-type stars. The purpose of this thesis is to optimize existing methods but also create new methodologies for determining stellar parameters that covers a very diverse group of stars. In Chapters 2 and 3, I describe the standard method of deriving stellar parameters for slowly rotating FGK stars that is based on the measurement of equivalent width (EW) of iron lines and by imposing ionization and excitation balance.
    [Show full text]
  • Solar System Analogues Among Exoplanetary Systems
    Solar System analogues among exoplanetary systems Maria Lomaeva Lund Observatory Lund University ´´ 2016-EXA105 Degree project of 15 higher education credits June 2016 Supervisor: Piero Ranalli Lund Observatory Box 43 SE-221 00 Lund Sweden Populärvetenskaplig sammanfattning Människans intresse för rymden har alltid varit stort. Man har antagit att andra plan- etsystem, om de existerar, ser ut som vårt: med mindre stenplaneter i banor närmast stjärnan och gas- samt isjättar i de yttre banorna. Idag känner man till drygt 2 000 exoplaneter, d.v.s., planeter som kretsar kring andra stjärnor än solen. Man vet även att vissa av dem saknar motsvarighet i solsystemet, t. ex., heta jupitrar (gasjättar som har migrerat inåt och kretsar väldigt nära stjärnan) och superjordar (stenplaneter större än jorden). Därför blir frågan om hur unikt solsystemet är ännu mer intressant, vilket vi försöker ta reda på i det här projektet. Det finns olika sätt att detektera exoplaneter på men två av dem har gett flest resultat: transitmetoden och dopplerspektroskopin. Med transitmetoden mäter man minsknin- gen av en stjärnas ljus när en planet passerar framför den. Den metoden passar bäst för stora planeter med små omloppsbanor. Dopplerspektroskopin använder sig av Doppler effekten som innebär att ljuset utsänt från en stjärna verkar blåare respektive rödare när en stjärna förflyttar sig fram och tillbaka från observatören. Denna rörelse avslöjar att det finns en planet som kretsar kring stjärnan och påverkar den med sin gravita- tion. Dopplerspektroskopin är lämpligast för massiva planeter med små omloppsbanor. Under projektets gång har vi inte bara letat efter solsystemets motsvarigheter utan även studerat planetsystem som är annorlunda.
    [Show full text]
  • The HARPS Search for Southern Extrasolar Planets: XXXIII. New
    Astronomy & Astrophysics manuscript no. final˙arx c ESO 2018 August 15, 2018 The HARPS search for southern extrasolar planets ? XXXIII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone. ?? G. Lo Curto1, M. Mayor2, W. Benz3, F. Bouchy2;5, G. Hebrard´ 5;6, C. Lovis2, C. Moutou4, D. Naef2, F. Pepe2, D. Queloz2, N.C. Santos7;8, D. Segransan2, and S. Udry2 1 ESO - European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Munchen,¨ Germany 2 Observatoire de Geneve,` Universite´ de Geneve,` 51 ch. des Maillettes, 1290 Sauverny, Switzerland 3 Physikalisches Institut Universitat¨ Bern, Sidlerstrasse 5, 3012 Bern, Switzerland 4 Laboratoire d’Astrophysique de Marseille, Traverse du Siphon, 13376 Marseille 12, France 5 Institut d’Astrophysique de Paris, UMR7095 CNRS, Universite´ Pierre & Marie Curie, 98bis boulevard Arago, 75014 Paris, France 6 Observatoire de Haute-Provence, CNRS/OAMP, 04870 Saint-Michel-l’Observatoire, France 7 Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal 8 Departamento de F´ısica e Astronomia, Faculdade de Ciencias,ˆ Universidade do Porto, Portugal ABSTRACT The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution. Well-defined volume-limited surveys are the best tool at our disposal to tackle the problem, via the acquisition of robust statistics of the orbital elements. We are using the HARPS spectrograph to conduct our survey of ≈ 850 nearby solar-type stars, and in the course of the past nine years we have monitored the radial velocity of HD103774, HD109271, and BD-061339.
    [Show full text]
  • Spectroscopic Parameters for Solar-Type Stars with Moderate-To-High Rotation New Parameters for Ten Planet Hosts?,??
    A&A 570, A80 (2014) Astronomy DOI: 10.1051/0004-6361/201424257 & c ESO 2014 Astrophysics Spectroscopic parameters for solar-type stars with moderate-to-high rotation New parameters for ten planet hosts?;?? M. Tsantaki1;2, S. G. Sousa1;2, N. C. Santos1;2, M. Montalto1, E. Delgado-Mena1, A. Mortier1, V. Adibekyan1, and G. Israelian3 1 Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal e-mail: [email protected] 2 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal 3 Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain Received 22 May 2014 / Accepted 25 July 2014 ABSTRACT Context. Planetary studies demand precise and accurate stellar parameters as input for inferring the planetary properties. Different methods often provide different results that could lead to biases in the planetary parameters. Aims. In this work, we present a refinement of the spectral synthesis technique designed to treat fast rotating stars better. This method is used to derive precise stellar parameters, namely effective temperature, surface gravity, metallicity, and rotational velocity. The procedure is tested for FGK stars with low and moderate-to-high rotation rates. Methods. The spectroscopic analysis is based on the spectral synthesis package Spectroscopy Made Easy (SME), which assumes Kurucz model atmospheres in LTE. The line list where the synthesis is conducted is comprised of iron lines, and the atomic data are derived after solar calibration. Results. The comparison of our stellar parameters shows good agreement with literature values, both for slowly and for fast rotating stars.
    [Show full text]
  • Analysis of Angular Momentum in Planetary Systems and Host Stars
    Analysis of Angular Momentum in Planetary Systems and Host Stars by Stacy Ann Irwin Bachelor of Science, Computer Science University of Houston 2000 Master of Science, Space Sciences Florida Institute of Technology 2009 A dissertation submitted to the College of Science at Florida Institute of Technology in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Space Sciences Melbourne, Florida July 2015 c Copyright 2015 Stacy Ann Irwin All Rights Reserved The author grants permission to make single copies We the undersigned committee hereby recommend that the attached document be accepted as fulfilling in part the requirements for the degree of Doctor of Philosophy in Space Sciences. \Analysis of Angular Momentum in Planetary Systems and Host Stars," a dissertation by Stacy Ann Irwin Samuel T. Durrance, Ph.D. Professor, Physics and Space Sciences Major Advisor Daniel Batcheldor, Ph.D. Associate Professor, Physics and Space Sciences Committee Member Darin Ragozzine, Ph.D. Assistant Professor, Physics and Space Sciences Committee Member Semen Koksal, Ph.D. Professor, Mathematical Sciences Outside Committee Member Daniel Batcheldor, Ph.D. Professor, Physics and Space Sciences Department Head Abstract Analysis of Angular Momentum in Planetary Systems and Host Stars by Stacy Ann Irwin Dissertation Advisor: Samuel T. Durrance, Ph.D. The spin angular momentum of single Main Sequence stars has long been shown to follow a primary power law of stellar mass, J M α, excluding stars of <2 solar masses. Lower mass / stars rotate more slowly with and have smaller moments of inertia, and as a result they contain much less spin angular momentum.
    [Show full text]
  • Age Consistency Between Exoplanet Hosts and Field Stars
    Astronomy & Astrophysics manuscript no. AAtransitsCitet c ESO 2021 September 16, 2021 Age consistency between exoplanet hosts and field stars A. Bonfanti1; 2, S. Ortolani1; 2, and V. Nascimbeni2 1 Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova, Italy 2 Osservatorio Astronomico di Padova, INAF, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy ABSTRACT Context. Transiting planets around stars are discovered mostly through photometric surveys. Unlike radial velocity surveys, photo- metric surveys do not tend to target slow rotators, inactive or metal-rich stars. Nevertheless, we suspect that observational biases could also impact transiting-planet hosts. Aims. This paper aims to evaluate how selection effects reflect on the evolutionary stage of both a limited sample of transiting- planet host stars (TPH) and a wider sample of planet-hosting stars detected through radial velocity analysis. Then, thanks to uniform derivation of stellar ages, a homogeneous comparison between exoplanet hosts and field star age distributions is developed. Methods. Stellar parameters have been computed through our custom-developed isochrone placement algorithm, according to Padova evolutionary models. The notable aspects of our algorithm include the treatment of element diffusion, activity checks in terms of 0 log RHK and v sin i, and the evaluation of the stellar evolutionary speed in the Hertzsprung-Russel diagram in order to better constrain age. Working with TPH, the observational stellar mean density ρ? allows us to compute stellar luminosity even if the distance is not available, by combining ρ? with the spectroscopic log g. Results. The median value of the TPH ages is ∼ 5 Gyr.
    [Show full text]
  • Binary Frequency of Planet-Host Stars at Wide Separations a New Brown Dwarf Companion to a Planet-Host Star,,, N
    A&A 569, A120 (2014) Astronomy DOI: 10.1051/0004-6361/201424210 & c ESO 2014 Astrophysics Binary frequency of planet-host stars at wide separations A new brown dwarf companion to a planet-host star,,, N. Lodieu1,2, A. Pérez-Garrido3,V.J.S.Béjar1,2, B. Gauza1,M.T.Ruiz4, R. Rebolo1,2,5, D. J. Pinfield6, and E. L. Martín7 1 Instituto de Astrofísica de Canarias (IAC), Calle Vía Láctea s/n, 38200 La Laguna, Tenerife, Spain e-mail: [nlodieu;vbejar;bgauza;rrl]@iac.es 2 Departamento de Astrofísica, Universidad de La Laguna (ULL), 38206 La Laguna, Tenerife, Spain 3 Universidad Politécnica de Cartagena, Campus Muralla del Mar, Cartagena, 30202 Murcia, Spain 4 Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile 5 Consejo Superior de Investigaciones Científicas, CSIC, Spain 6 Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB, UK 7 Centro de Astrobiología (INTA-CSIC), Departamento de Astrofísica, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain Received 14 May 2014 / Accepted 4 August 2014 ABSTRACT Aims. The aim of the project is to improve our knowledge on the multiplicity of planet-host stars at wide physical separations. Methods. We cross-matched approximately 6200 square degree area of the southern sky imaged by the Visible Infrared Survey Telescope for Astronomy (VISTA) Hemisphere Survey (VHS) with the Two Micron All Sky Survey (2MASS) to look for wide com- mon proper motion companions to known planet-host stars. We complemented our astrometric search with photometric criteria. Results. We confirmed spectroscopically the co-moving nature of seven sources out of 16 companion candidates and discarded eight, while the remaining one stays as a candidate.
    [Show full text]